Composite thermal transfer system for closed cycle engines

ABSTRACT

The composite thermal transfer system consists of both internal and external means for rapidly transferring heat into the hot side, and removing heat from the &#39;&#39;&#39;&#39;cold,&#39;&#39;&#39;&#39; heat sink side of C.C.E.&#39;&#39;s. The external transfer arrangement consists of both conventional heating and cooling means along with hot and freezing cold air flow from seried air temperature splitters. The internal transfer arrangement consists of multiple conduction rods within the hot and cold sides of the C.C.E. The cooling conduction rods carry liquid coolant into and out of each rod and are independently connected to a liquid coolant manifold reservoir. The hot conduction rods are hollow so that tiny burner tubes provide heating all along the length of the rod bore, and thereby into the engine hot gas volume. The combined external and internal thermal transfer system provides a means of overcoming the usual heat transfer difficulties, particularly in the Stirling and Brayton cycle machines, but is also adaptable to Rankine cycle machines.

ilitited States Patent Kelly 1 Jan. 18, 1972 COMPOSITE THERMAL TRANSFER SYSTEM FOR CLOSED CYCLE ENGINES [72] lnventor: Donald A. Kelly, 58-06 69th PL, Maspeth, New York, NY. 11378 22 Filed: Apr. 23, 1970 211 Appl.No.: 31,269

52 us. CI. ..60/24 I51 Int. Cl. ..F03g 7/06 158] Field 01 Search ..60/24, 27

I56] References Cited UNITED STATES PATENTS 3,415,054 12/1968 Schulze ..60/24 3,496,720 2/1970 Neelen et a1 60/24 FOREIGN PATENTS OR APPLICATIONS 772,753 '1957 Great Britain ..60/24 Primary Examiner-Edgar W. Geoghegan Assistant Examiner-Allen M. Ostrager [57] ABSTRACT The composite thermal transfer system consists of both internal and external means for rapidly transferring heat into the hot side, and removing heat from the cold," heat sink side of C.C.E.s.

The external transfer arrangement consists of both conventional heating and cooling means along with hot and freezing cold air flow from seried air temperature splitters The internal transfer arrangement consists of multiple conduction rods within the hot and cold sides of the C.C.E. The cooling conduction rods carry liquid coolant into and out of each rod and are independently connected to a liquid coolant manifold reservoir. The hot conduction rods are hollow so that tiny burner tubes provide heating all along the length of the rod bore, and thereby into the engine hot gas volume.

The combined external and internal thermal transfer system provides a means of overcoming the usual heat transfer difficulties, particularly in the Stirling and Brayton cycle machines, but is also adaptable to Rankine cycle machines.

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INVLN70R JM/ 0% COMPOSITE THERMAL TRANSFER SYSTEM FOR CLOSED CYCLE ENGINES The thermal transfer system for closed cycle engines, (C.C.E.'s) is advocated as a means of overcoming the basic difficulties of rapid heat transfer through metal surfaces for Stirling, Brayton and Rankine closed cycle engines and turbines.

This problem has kept these desirable heat engines from wide use and general acceptance, since the LC. engine was a readily available and convenient power source, so that the C.C.E.s have been generally regarded as academic heat engine cycles with few practical commercial applications.

Since it is doubtful that the conventional l.C. engine can provide a long range solution to the vehicular toxic emission problem, it is advocated that some type of closed cycle engine or turbine be universally adopted as the standard vehicular power source for all urban areas.

Conventional LC. engines with the addition of numerous and various emission control devices will be subject to constant degrading and readjustment, with the loss of usual performance and ease of maintenance.

The composite thermal transfer system is comprised of an external and internal heat exchange arrangement which complement each other so that rapid and effective heat transfer is accomplished. Since internal heat transfer is dependent on large transfer surface areas, the utilization of multiple conduction rods for both hot and cold engine sides is a useful arrangement.

The use of multiple conduction rods is particularly suited to Stirling cycle piston engines because the rods may clear corresponding clearance bores within the displacer piston, as the piston or pistons reciprocate.

The multiple conduction rods may be utilized in Brayton and Rankine cycle turbines by incorporating the rod concept into the stationary stator vanes or blades, or by adding separate vanes in a radial array between the turbine operating stages.

Multiple cold conduction vanes would be uniformly placed along the cold duct sections between the compressor stages, while the multiple hot conduction vanes would be uniformly located near the heater in the heating duct section between the heater and the power stage. In the Brayton cycle turbines the stationary aerodynamic blades could be provided with burner tubes in the power stage, and coolant bores in the compressor stage stator blades.

The cold" heat sink conduction vanes would contain two parallel incoming and outgoing bores and a cross-connection bore at the blind end, for full circulation of the liquid coolant throughout the rocl's length. It is most important that each cooling conduction rod with the liquid conducting bores be independently connected to the liquid coolant reservoirs, rather than in a series arrangement. lndependent connection assures that a more rapid circulation and heat exchange is made to and from the reservoirs, which in turn are connected to the external heat transfer arrangement.

Each reservoir, incoming and outgoing, would contain a liquid coolant pump to maintain uniform circulation of the coolant through the multiple cold conduction rods. The problem of making simplified connection loops and maintaining liquid tight sealing between the conduction rod bores and the transfer bores within the conduction plate is simplified by having the plate bores connect with the conduction rods through cross bores and sealing gaskets.

The ends of the bores at the outer face of the conduction rods are lined up with the transfer bores in the conduction plate for completion of each coolant circulation loop. External connections are made to each reservoir from the conduction plate bores where they exit at the edge of the conduction plate.

The hot conduction rods are provided with as large a diameter blind bore that is possible, consistent with maintaining pressure tight integrity.

Small diameter, long burner tubes are placed within the blind bores which nearly match the blind bores length. Tiny burner orifices are uniformly located along the burner tube which provide equalized heating all along the length of the hot conduction rod bore, so that the rod is unifonnly heated and in turn the working hot gas volume within the closed cycle engine or turbine.

The long, thin burner tubes may be pressurized and operate on fuel fed from a conveniently located fuel tank. The burner tubes may also be fired by propaneor other gas, instead of kerosene or other liquid fuel. All the burner tubes are brought out of the conduction rods together for ignition and are inserted slowly so that combustion is maintained.

It is recognized that the described internal conduction rod transfer method is fairly complex and requires careful sealing techniques which may result in a higher cost system, but it is believed to be a workable way of reaching high thermal effectiveness, particularly in Stirling cycle engines, and Brayton cycle turbines. The choice of this arrangement must be consistent with the type of application, allowable costs, and efficiency level required.

The Stirling and Brayton closed cycle machines may possibly be cooled without a circulating liquid coolant arrangement if external finned-ducting is provided with the freezing airflow from thermal air splitters directed over the entire length of the finned-ducting. It is desirable to arrange the gaseous closed cycle machines without external ducting if possible, for compactness and simplicity in manufacturing, but if the necessary power output is not achieved by this arrangement, the external ducting and freezing air fiow may be utilized.

The external heat transfer arrangement consists of a conventional heater unit or units fuelded by any liquid or gaseous fuel. The heater unit would be in close contact with the hot side of the engine with a maximum of surface area in contact. Provision is made for the passing through of the internal heat conduction rods of the internal system, without undue loss of surface area for the external heater unit.

The external cooling arrangement will consist of a conventional liquid coolant jacket and circulating means and this supported or augmented by the freezing air flow from air thermal splitters in a series array.

The seried thermal air splitters may also be used alone for some applications which may not require both a liquid and air cooling arrangement.

The thermal air splitters would be driven by incoming ram air when the vehicle is in motion and by an auxiliary drive from the engine during starting.

DESCRIPTION OF DYNAMIC AIR SPLITTER The dynamic air splitter" refers to the device known in the art as the Foa energy separator, developed by Professor Joseph Foa, (US. Pat. No. 3,36l,33ldated Jan. 2, 1968). One of the objects of this present patent application is the specific use of this device to the cooling of the working medium in a closed cycle engine system.

The Foa device is essentially a combined air compressor and expander, which divides or splits an air flow intorelatively hot and cold air streams. They key feature in the device is that the moving air delivery means (tubes, vanes, etc.) is sloped or angled relative to a stationary housing surface.

On the acute side of the moving air delivery means, the air tends to be compressed, and therefore heated, while on the obtuse angle side the air is expanded, and therefore cooled."

The present device has a relatively low cooling efficiency- (10 percent to 15 percent) which may be improved, and should be useful when run at high speeds by a small auxiliary power takeoff.

It is an object of their invention to provide a combined in ternal and external heat transfer system for all types of closed cycle engines and turbines.

It is an object of the invention to produce an effective thermal transfer system for any type of closed cycle engine.

It is a final object of the invention to provide a composite thermal transfer system which justifies it use on a cost/effectiveness basis.

It should be understood that variations may be made in the detail design of the composite thermal transfer system without departing from the spirit and scope of the invention.

Referring to the drawings:

FIG. 1 is an elevation view of the internal transfer arrangement for a Stirling type of C.C.E.

FIG. 2 is an elevation view of the external transfer arrangement for a C.C.E.

FIG. 3 is an elevation view of a Brayton closed cycle turbine with the composite thermal transfer system in use.

FIG. 4 is an elevation view of a Rankine closed cycle turbine with the composite thermal transfer system in use.

FIG. 5 is a cross section view through a cooling rod or vane.

FIG. 6 is a cross section view through a heating rod or vane.

FIG. 7 is an end section through an alternate cooling vane with a single bore and separator strip.

FIG. 8 is a cross section view through a cooling duct showing the external/internal cooling vanes.

Referring to the drawings in detail:

A Stirling type of closed cycle engine 1, is provided with heat conduction rods 2, within the hot displacer volume 3, and cooling conduction rods 4, within the cold heat sink volume 5.

A bored piston member Ia, reciprocates within the engine. The piston Ia, contains multiple axially disposed bores lb, which provide sufficient clearance for the hot and cold conduction rods 2 and 4, respectively, as the piston 1a reciprocates within the engine 1.

The heat conduction rods 2, are provided with blind bores 6, which run nearly the full length of the rods. The inner ends of the rods 2, are rounded at 7, and threaded near the outer end 8. A stop flange 9, limits the distance that the heat conduction The outer conduction plate 14, contains the liquid coolant circulation bores I6,w which are connected to the rod blind bore20, by the corssbores 17. The corssbores 17, are sealed by the plugs 18, at the outside of the outer conducion plate 14. rods 2, can be inserted into the hot displacer volume 3. The thin burner tubes 23, are fitted into the blind bores 6, of the heat conduction rods 2, and provide for the necessary heating of the rods. Fuel is supplied to the burner tubes 23, through the tubing 24, from the fuel tank 25.

The cooling conduction rods 4, are provided with two, parallel blind bores 10, which run nearly the full length of the rods and are connected near the inner end by the crossbore 11, and sealed by the plug 12.

Two cold conduction plates 13 and 14, support the cooling conduction rods 4, and impliment the circulation of the liquid coolant through each of the rods. The inner conduction plate 13, directly secures each of the cooling conduction rods 4, with the threaded holes 15.

Approximately ten cooling conduction rods 4, are uniformly arrayed around the perimeter of the inner conduction plate 13, so that the central back and forth air flow is not impeded.

The outer conduction plate 14, contains the liquid coolant circulation bores 16, which are connected to the rod blind bores 10, by the crossbores 17. The crossbores 17, are sealed by the plugs 18, at the outside of the outer conduction plate 14.

A counterbore 19, is provided in the outer conduction plate 14, in which the stop flanges 9, of the cold conduction rods 4, closely fits. A sealing gasket 20, with two corresponding holes which line up with the blind bores 10, is fitted between the top of each stop flange 9, and the base of the counterbores 19.

The liquid circulation bores 16, are located in the outer conduction plate 14, so that they uniformly terminate at the edge of the conduction plate, preferably at the top and two sides. Connecting tubes 21, join the ends of the bores 16, with the two manifold reservoirs 22. one incoming and the other outgoing, which in turn are connected to the external transfer system.

In the external heating arrangement a convention fuel burner unit 26, is in close contact with a maximum surface area of the hot engine side. Ports 27, are provided in the fuel burner unit 26, for the passing through of the heat conduction rods 2, without excessive loss of surface heating area.

The multiple burners 28, are uniformly placed within the burner unit 26, with fuel lines 29, running to the fuel tank 25. The multiple burner units may be pressurized for combustion effectiveness, by an air line 30, from a compressor 31.

The external cooling arrangement consists of a convention liquid cooling means comprised of a heat exchange radiator 32, connected by coolant lines 33, to the two manifold reservoirs 22, in a series loop. Two liquid pumps 34, are located in each manifold reservoir 22, which both move the coolant in one direction and through each of the cooling conduction rods 4.

In addition to liquid cooling, cold or freezing air flow from air temperature splitters 35, may be utilized to direct air flow over the cold engine side and through the heat exchange radiator, 32.

For some C.C.E. types and certain applications, the air temperature splitters may be used alone without a liquid cooling system. The air temperature splitters 35, may be used in a seried arrangement, and are driven by the incoming ram air from the air intake scoops 44, by means of the rotary impellers 45. In the Brayton closed cycle turbine with an external cooling duct 36, arrangement multiple uniformly disposed through-the-duct cooling vanes 37, are utilized to cool the working gas passing through on the way to the compressor stage. The air flow from the air temperature splitters 35, is directed along the length of the cooling duct 36, and along each of the cooling vanes 37, so that heat is removed with the cold air stream.

Multiple cooling conduction vanes 38, carrying liquid coolant similar to the cooling conduction rods, may be utilized in the cooling ducts 36, and cold sections of the Brayton closed cycle machines.

Heating conduction rods or vanes 2, may be placed in the heating section or ducts of the closed cycle turbines.

Heating blades 39, and cooling blades 40, similar to the hot and cold conduction rod technique may be placed as stator blades in the turbine section and compressor stage, respectively to increase the thermal range and effectiveness of these engine cycles.

The heating arrangement for the Brayton closed cycle turbine would consist of a diffuser/heater 46, of maximum length placed between the compressor stage and the expanding gas flow to the turbine. The compressed gas flow from the compressor is uniformly heated and diffused before entering the turbine stage. The multiple difluser bores 41, are tapered with the larger diameters 42, located adjacent to the power turbine, The thermal transfer for the Rankine closed cycle turbine is generally similar to the Brayton cycle, with the exception of the cooling function. A condenser 43, is utilized, along with the described cooler, in which the steam vapor is condensed and the resultant water returned to the boiler for reheating and the continuation of the cycle.

What is claimed: 1. A composite heat transfer system for closed cycle engines comprising coacting internal and external heat exchanging means,

multiple internal conduction rods uniformly disposed within the hot displacement volume of said closed cycle engine,

multiple elongate blind bores centrally disposed within said multiple internal conduction rods, support means for said multiple internal conduction rods within said closed cycle engine,

multiple thin elongate burner tubes centrally positioned within said multiple elongate blind bores,

liquid or gaseous fuel ignited within said multiple thin elongate bumer tubes,

fuel storage and delivery means for said multiple thin elongate bumer tubes adjacent to said closed cycle engine,

sealing means within said support means for the connecmultiple internal cooling conduction rods uniformly disposed within the cold contraction volume of said closed cycle engine,

support means for said multiple internal cooling conduction rods disposed within said closed cycle engine, 5

multiple dual parallel incoming and outgoing blind bores uniformly disposed within said multiple internal cooling conduction rods,

a liquid coolant circulation loop means connecting each of said multiple dual parallel incoming and outgoing blind bores with liquid conducting tubing to two manifold liquid coolant reservoirs,

pumping means within said two manifold liquid coolant reservoirs,

tions of said multiple internal cooling conduction rods,

an externally mounted burner unit in close contact with a maximum surface area of the hot side of said closed cycle engine,

multiple burner manifold tubes uniformly disposed within the said externally mounted burner unit,

uniformly disposed clearance ducts within said externally mounted burner unit for said multiple internal conduction rods,

liquid or gaseous fuel ignited at each of the said multiple burner manifold tubes,

fuel storage and delivery means for said multiple burner manifold tubes, multiple air temperature splitters uniformly disposed with freezing/cold air flow directed over the cold heat sink side of said closed cycle engines,

a heat exchanging radiator in line with some of the freezing/cold air flow from said multiple air temperature splitters,

liquid coolant conducting lines connecting said heat 35 exchanging radiator with the said two manifold liquid coolant reservoirs,

ram air scooping means associated with each of said multiple air temperature splitters disposed at the front of said closed cycle engine,

auxiliary drive means for powering said multiple air temperature splitters from said closed cycle engines.

2. A composite heat transfer system for closed cycle engines according to claim 1, wherein the freezing/cold air flow from said multiple air temperature splitters is directed over the elongate surfaces of cold transfer ducts associated with closed cycle turbines,

multiple heat transfer vanes uniformly disposed at right angles and through said cold transfer ducts,

symmetrically elongate vane extensions at either surface of said cold transfer ducts,

uniform angular staggering of said multiple heat transfer vanes along said cold transfer ducts.

3. A composite heat transfer system for closed cycle engines according to claim 1, wherein multiple internal conduction airflow vanes are uniformly disposed as stator vanes between the rotor sections of the power stage of a turbine,

multiple internal cooling conduction airflow vanes are uniformly disposed as stator vanes between the rotor sections of the compressor stage of a turbine.

4. A composite heat transfer system for closed cycle engines according to claim I, wherein the said multiple air temperature splitters are rotated by impellers driven by incoming air flow from said ram air scooping means,

separate air delivery means within said ram air scooping means for driving said impellers.

5. A composite heat transfer system for closed cycle engines according to claim 1, including a diffusing-type heater of maximum length disposed between a compressor stage and power turbine of said closed cycle engine,

multiple diffuser bores uniformly disposed within said diffusing-type heater with the larger diameter disposed adjacent to apower stage of said closed c cle engine. I 6. A compost e heat transfer system for c osed cycle engines according to claim 1, wherein said multiple internal conduction rods are uniformly disposed within various sections and ducts of said closed cycle engines,

multiple internal cooling conduction rods uniformly disposed within various cold sections and ducts of said closed cycle engine.

7. A composite heat transfer system for closed cycle engines according to claim 1, wherein said multiple internal conduction rods are utilized in Rankine closed cycle turbines,

multiple internal cooling conduction rods are utilized within the condenser of Rankine closed cycle turbines. 

1. A composite heat transfer system for closed cycle engines comprising coacting internal and external heat exchanging means, multiple internal conduction rods uniformly disposed within the hot displacement volume of said closed cycle engine, multiple elongate blind bores centrally disposed within said multiple internal conduction rods, support means for said multiple internal conduction rods within said closed cycle engine, multiple thin elongate burner tubes centrally positioned within said multiple elongate blind bores, liquid or gaseous fuel ignited within said multiple thin elongate burner tubes, fuel storage and delivery means for said multiple thin elongate burner tubes adjacent to said closed cycle engine, multiple internal cooling conduction rods uniformly disposed within the cold contraction volume of said closed cycle engine, support means for said multiple internal cooling conduction rods disposed within said closed cycle engine, multiple dual parallel incoming and outgoing blind bores uniformly disposed within said multiple internal cooling conduction rods, a liquid coolant circulation loop means connecting each of said multiple dual parallel incoming and outgoing blind bores with liquid conducting tubing to two manifold liquid coolant reservoirs, pumping means within said two manifold liquid coolant reservoirs, sealing means within said support means for the connections of said multiple internal cooling conduction rods, an externally mounted burner unit in close contact with a maximum surface area of the hot side of said closed cycle engine, multiple burner manifold tubes uniformly disposed within the said externally mounted burner unit, uniformly disposed clearance ducts within said externally mounted burner unit for said multiple internal conduction rods, liquid or gaseous fuel ignited at each of the said multiple burner manifold tubes, fuel storage and delivery means for said multiple burner manifold tubes, multiple air temperature splitters uniformly disposed with freezing/cold air flow directed over the cold heat sink side of said closed cycle engines, a heat exchanging radiator in line with some of the freezing/cold air flow from said multiple air temperature splitters, liquid coolant conducting lines connecting said heat exchanging radiator with the said two manifold liquid coolant reservoirs, ram air scooping means associated with each of said multiple air temperature splitters disposed at the front of said closed cycle engine, auxiliary drive means for powering said multiple air temperature splitters from said closed cycle engines.
 2. A composite heat transfer system for closed cycle engines according to claim 1, wherein the freezing/cold air flow from said multiple air temperature splitters is directed over the elongate surfaces of cold transfer ducts associated with closed cycle turbines, multiple heat transfer vanes uniformly disposed at right angles and through said cold transfer ducts, symmetrically elongate vane extensions at either surface of said cold transfer ducts, uniform angular staggering of said multiple heat transfer vanes along said cold transfer ducts.
 3. A composite heat transfer system for closed cycle engines accOrding to claim 1, wherein multiple internal conduction airflow vanes are uniformly disposed as stator vanes between the rotor sections of the power stage of a turbine, multiple internal cooling conduction airflow vanes are uniformly disposed as stator vanes between the rotor sections of the compressor stage of a turbine.
 4. A composite heat transfer system for closed cycle engines according to claim 1, wherein the said multiple air temperature splitters are rotated by impellers driven by incoming air flow from said ram air scooping means, separate air delivery means within said ram air scooping means for driving said impellers.
 5. A composite heat transfer system for closed cycle engines according to claim 1, including a diffusing-type heater of maximum length disposed between a compressor stage and power turbine of said closed cycle engine, multiple diffuser bores uniformly disposed within said diffusing-type heater with the larger diameter disposed adjacent to a power stage of said closed cycle engine.
 6. A composite heat transfer system for closed cycle engines according to claim 1, wherein said multiple internal conduction rods are uniformly disposed within various sections and ducts of said closed cycle engines, multiple internal cooling conduction rods uniformly disposed within various cold sections and ducts of said closed cycle engine.
 7. A composite heat transfer system for closed cycle engines according to claim 1, wherein said multiple internal conduction rods are utilized in Rankine closed cycle turbines, multiple internal cooling conduction rods are utilized within the condenser of Rankine closed cycle turbines. 